This project examines the relationship among dietary sodium, insulin resistance, and cardiovascular reactivity in normotensive and mildly hypertensive Black and White men. All 80 subjects will undergo within subject manipulation of dietary sodium involving two separate stays in the GCRC. On high (200mEq/d for 8 days) and low (10mEq/d for 8 days) sodium diets, subjects will undergo a series of assessment procedures including 24hr. urine collections and 24hr. ambulatory BP monitoring, OGTT, postural challenge, and insulin clamp.